1. Field of the Invention
The present invention relates to a system for leakproof packaging of goods, particularly perishable food products.
2. Description of the Prior Art
Various types of container systems have been utilized to package perishable goods, such as food products. The packaging of food products for shipment in compartmentalized containers presents several problems, the solutions to which are sometimes in conflict. It is highly desirable for perishable food to be shipped in containers that provide a high degree of cushioning to prevent damage to the food products that would otherwise result from the impacts to the containers that inevitably occur during loading and unloading, and during transportation on a vehicle. Unfortunately, many of the best cushioning systems are quite bulky, thereby reducing the quantity of perishable goods that can be packed within a limited volume of space.
Another conflict in packaging of perishable goods that exists involves the matter of protection from leakage. While it is entirely possible to devise leakproof containers, many conventional leakproof packages are quite bulky. Some are also quite heavy. Nevertheless, unless the packages are rendered leakproof, the escape of moisture damages outer shipping cartons in which the goods are packaged, which can easily lead to damage to the food products during unloading. Such leakage also creates messes in the transport vehicles and in storage areas. These messes must be cleaned up, thus increasing the labor expense involved in shipping and storage.
Another problem that exists in packaging perishable food products for shipment is that the empty containers that are used to protect the goods during shipment present a storage problem when they are not actually in use. To solve this problem I previously devised an insulated container for packaging perishable goods which is fully collapsible so that large numbers of these containers can be stored within a compact volume. These containers, and their construction, are described in my prior U.S. Pat. Nos. 5,820,268 and 6,007,467.
However, I have since discovered certain shortcomings in my prior design. Specifically, these container devices involve seams between adjacent abutting edges that are secured by tape or edge line heat sealing. In both of these sealing systems the edges of a sheet of material that must be joined are brought together in abutting relationship and then sealed. Unfortunately, edges sealed in this manner are drawn apart by stress at their junction so that leakage occurs with disturbing frequency. Also, both the collapsing and deployment of these containers requires a number of steps of manual manipulation. While such steps can be performed rather quickly on a single container, the time required is unacceptably great when a large number of these containers must be deployed for use or collapsed following use.
The present invention provides an extremely useful and simple container for shipping perishable goods that overcomes many of the difficulties of prior devices employed for this purpose. In one broad aspect the present invention may be considered to be a collapsible shipping container comprising at least one sheet of flexible, thermally insulating material having mutually parallel linear side edge fastening margins. The sheet or plurality of sheets are folded to form a rectangular floor and four walls projecting from the floor in orthogonal relation relative to the floor to define an enclosure. The linear side edge fastening margins meet in facing relationship and are heat sealed throughout interfaces of mutual contact, whereby the edge margins are directed outwardly from the exterior of the enclosure.
The sheet or sheets of material used in the fabrication of the collapsible shipping container of the invention are preferably formed of plastic, white, bubble packing material faced on both sides with plastic film layers. This material provides very good thermal insulating properties, is impervious to moisture, and creates a very good overall insulating effect without occupying a great volume of space. One suitable alternative construction may employ sheet material formed of a plastic foam layer faced on one side with a plastic film layer.
Preferred embodiments of the invention may take several forms. In one preferred embodiment the shipping container is comprised of first, second, and third sheets of material as previously described. The first sheet has an elongated shape with mutually parallel side edge margins and mutually opposing end sections with a center section located therebetween. The second and third sheets of material are shorter than the first sheet and both have bottom attachment edge margins that are heat sealed to opposing ones of the side edge margins of said first sheet at said center section thereof. The second and third sheets have side edge margins extending perpendicular to the side edge margins of the first sheet. The side edge margins of the second and third sheets are heat sealed to the side edge margins of the first sheet which together form the aforesaid linear side edge fastening margins. The end sections of the first sheet and the second and third sheets form the four walls and the center section of the first sheet forms the floor of the collapsible shipping container of the invention.
In the foregoing embodiment which is formed of three sheets joined together the floor is foldable inwardly toward the enclosure along a floor folding line that bisects the floor and extends between the second and third sheets. The second and third sheets are both foldable inwardly toward the enclosure along wall folding lines that are parallel to the side edge margins of the second and third sheets and which are equidistant therefrom. In this way the floor is foldable in half and the end sections of the first sheet are collapsible into contact with each other.
Preferably, one of the first sheet end sections is longer than the other and thereby forms a flap that folds over a portion of the other first sheet end section. The provision of a closure flap makes it easier to seal the container and preserve liquid tight integrity of the container and the freshness of food products encapsulated therein.
In another embodiment of the invention the collapsible shipping container is formed from a single, elongated, rectangular sheet of flexible, thermally insulating material having the side edge fastening margins in the direction of its length and delineated into a larger panel and a smaller panel. The smaller panel forms a pouch apron end section which is folded back against the larger panel whereby the side edge fastening margins are doubled back upon themselves and are sealed throughout the length of the smaller panel. The portion of the larger panel against which the pouch apron end section is sealed may be considered to be an intermediate section of the sheet. A portion of the larger panel extends from the intermediate section beyond the smaller panel to form a foldable closure flap end section. The mutually adjacent portions of the larger and smaller panels at the demarcation therebetween and which are located interiorly from the side edge fastening margins are flattenable into a common plane to form the floor, while the remaining portions of the larger and smaller panels form the four walls and also form a pair of triangular shaped pockets that extend from the floor. This embodiment of the shipping container of the invention can thereby be transformed from a flattened pouch to a laterally expanded container by pressing the upper portions of the heat sealed fastening margins toward each other while pressing downwardly on the lower portions of the fastening margins.
The invention may be described with greater clarity and particularity by reference to the accompanying drawings.